Açai reverses age-related cognitive decline in rat study

Açai fruit fed to aged rats reversed age-related cognitive and motor declines, a study conducted through Tufts University has found.

The study, which was presented at the recently-concluded Society for Neuroscience meeting that was held in New Orleans, fed old rats diets that included 2% of one of two açai species, euterpe oleracea, found mostly along the Amazon river near its mouth and euterpe precatoria, found in Bolivia. The rats, divided into three groups, were then put through a battery of cognitive and motor skills tests. The rats fed the açai performed significantly better than the standard diet control group.

“Any time that we can alter memory performance in older animals it is pretty significant,” lead researcher Barbara Shukitt-Hale, PhD, of Tufts University told NutraIngredients-USA.

“We have shown similar results from blueberries and strawberries, but acai has a little different structure.”

Study used pyschomotor, memory tests

The rats were fed the açai diets for seven weeks prior to the motor skills and six weeks prior to the cognitive testing. Their psychomotor behavior was tested with a battery of age-sensitive tests that included rod walking, wire suspension and plank walking to test balance, muscle strength and fine motor coordination. Each of the tests were performed once.

The cognitive testing was performed with the working memory version of the Morris water maze test, in which a rat swims in a container of water until it finds a submerged platform not visible from the surface but shallow enough so that the rat can rest. The test measures how well the rat remembers the location of the platform by measuring both the time it takes to find the platform again and the distance the rats swam, to control for faster swimmers.

The tests were performed daily for four consecutive days, with two trials each session. A rat was given 120 seconds to find the platform; if it didn’t find it within the time limit it was guided onto it. After a 10 minute rest, it was introduced into the tank at the same starting point with the platform in the same position, with the amount of time to find the platform the second time measured.

Açai improved memory

Both açai groups showed improved working memory on days 1 and 2 of the tests, when the animals were still learning the task. They also showed better reference, or spatial, memory on days 3 and 4 of the water maze tests.

The rats’ brain tissues have been harvested, and await further study to determine if alterations in signaling and autophagy could help explain the mechanisms of action by with the polyphenols in the açai could be having their effects.

Interestingly, there was a difference between the results between the two açai species. Euterpe precatoria (EP) has about 2.5 times the phenolic content of euterpe oleracea (EO) (320 ng/mg as compared to 133 ng/mg) and an ORAC value of 7698 vs. 2649 (umol TE/g, DW). Yet the EO showed improved benefits overall, even when delivering lower amounts of the polyphenolic compounds.

This points to a possible sweet spot in the dose of polyphenols. The study’s summary suggests that the 2% dose for the EP may have been too high, given its greater concentration of polyphenols. It’s something the Tufts’ researchers have run across before when working with polyphenols, Shukitt-Hale said.

“A while ago we had done a grape juice study, in which the animals were drinking the juice. Some animals got a 10% solution and others got a 50% grape juice solution. The ones that got the 10% solution did better on the cognition testing,” she said.

The study, conducted at the United States Department of Agriculture lab associated with Tufts University with funding support from Salt Lake City-based MonaVie LLC and additional support from Seattle-based AIBMR Life Sciences, concluded that açai shows promise in the healthy aging space, by reducing the incidence and/or delaying the onset of debilitating neurodegenerative diseases.

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